Supergirl Recap With Spoilers: For The Girl Who Has Everything

The episode opens as Kara wakes up on Krypton.

Kelex, a robot who's maintaining her, talks to her -- and then Alura comes and tells her that she's had a fever and must have had terrible hallucations, but now she's safe and home.

At CatCo, Cat wonders where Kara is and why she can't answer her cell phone. Winn says nobody can reach her because of a solar storm that's disrupting communications, but when Jimmy hasn't heard from her either, they call Alex...who breaks into Kara's apartment to find her sister on the ground, an alien plant on her chest.

At the DEO, Henshaw has Olsen and Winn kicked out. Alex says that Kara's body is unresponsive but her brain is normal. She has a theory about where the plant comes from -- and she goes to attack Max in his cell, but he doesn't know what she's talking about.

Elsewhere, Non tells Astra that he used a Black Mercy on Kara, so she's unharmed but not a threat to them.

At the DEO, Henshaw and Alex use a machine to try and remove the Black Mercy, but when they start to get it off her body, it starts to kill her.

On Krypton, Kara knows that this Krypton isn't real -- but starts to doubt that when she sees a little statue she made for her father as a child. She tells her mother she's fantasized about all of this every day since she left, and that when she figures out what's happening, she's going home.

At CatCo, James tells Winn that Kara is going to be fine and that they have to cover for Kara to help her keep her job. Cat, still fuming about the Adam thing, tells Winn to tell Kara that they want her back at work within an hour or she's fired.

At the DEO, Henshaw is furious and frustrated that the organization can't function while their communications satellite is down. Alex convinces him to go fill in for Kara at CatCo, but it goes about as well as one would imagine with Cat.

At the DEO, Alex is asking the holographic Alura for information about the Black Mercy, but she's getting nowhere with it.

On Krypton, Kara sees her father -- and starts losing her memories of Earth. When Astra comes into the room, Kara realizes it must be Astra and Non who have done this to her. Just as she's trying to figure out what's going on, Kal-El comes in and brings her a little globe that she opens, projecting the solar system into the air around them.

Back on Earth, Alex is in Kara's apartment, looking at photos of the two of them, when Astra comes to her. Astra tells Alex that they have to guide Kara to reject the fantasy of the Black Mercy herself, there's nothing they can do directly. Astra realizes that the two are sisters, and offers her help despite Alex's resistance.

At CatCo's IT room, Alex tells Henshaw, Winn and James that she plans to modify their virtual reality computers so that she (Alex) can enter Kara's dream and guide her out. She takes James and Winn to be side by side when Kara wakes up in trauma.

Henshaw shifts into Kara and manages to talk Cat into giving "her" the day off. Then back at the DEO, Henshaw and Alex recruit Max Lord to help them prepare the virtual reality thing.

At their hideout, Non confronts Astra about her disappearance, but she convinces him that she's committed to the cause and won't have done anything to hurt their chances of a successful invasion.

Back at the DEO, Max gives Alex a VR headset and sends her into Supergirl's fantasy. Before she goes, she tells James that he has to make sure Henshaw doesn't pull her out until after she's saved Kara.

Winn, figuring out that the Kryptonians might be using Earth technology against them, and that their plans might have something to do with the satellites. Henshaw sends Winn to their computers to work with his team on the theory.

On Krypton, Alex approaches Kara, who doesn't believe her or remember Earth, and punches Alex out.

Henshaw wants to pull Alex out, but James convinces him not to.

Back inside the fantasy, the Kryptonians sentence Alex to banishment to the Phantom Zone. Before her sentencing, Alex breaks down, begging Kara to remember reality and saying that life isn't perfect. As she fights with her captors, reminding Kara about her responsibilities as Supergirl, the world outside starts to experience seismic tremors. Kara starts to realize that Alex is right, and Krypton starts to crumble around her.

She tells her family that she wants so much for the fantasy to be true, but she knows she can't. She says goodbye to her family, and that Krypton will be in her heart forever, but that she has to go.

Alex wakes up in the DEO, followed by Kara, while the Black Mercy crawls off her and across the floor. Kara is distant, near tears, and finally furious over what she's just been subjected to. She damands to know who did this to her, and when she's told it's Non, she asks where he is.

Winn tells the DEO that he's found some hidden transmissions from Earth satellites, all of which use Lord Tech servers from the lab Non attacked. Apparently, they've been using his satellites to overwrite civilian transmissions. Lord tells them where other targets might be, and they scramble teams to those places.

As Non makes his way into one of those locations, Supergirl charges into him, battering him in a fury.

Elsewhere, a DEO team including Alex goes after Astra, who's trying to sabotage another satellite. Alex tells her she doesn't believe Astra wants to kill Kara, and asks for her help.

Martian Manhunter arrives, fighting with her briefly.

Elsewhere, Non rants at Supergirl, but she keeps beating on him. Eventually he tells her that humanity is a disease and Myriad, their plan, is the cure. He knocks her back with heat vision and installs something on the satellite.

Back at the other battle, Astra is about to kill Martian Manhunter when Alex stabs her through the back with a Kryptonite sword.

Non uses his heat vision on a giant satellite dish, endangering nearby people, and while Kara rescues them, he escapes. Alex calls Kara.

As Astra lays dying, she says she's glad Alex was able to bring Kara back. Kara tells her that when she saw her perfect life, Astra was there. Astra warns her against trying to stop Non, saying it can't be done, and then dies before she can tell Kara what Myriad is. Kara, Alex and Henshaw retreat as a trio of Kryptonians descend on Astra's body.

Later, at their lair, Non mourns the loss of his wife. Another soldier consoles him, saying she died a hero.

At The DEO, Henshaw tells Alex she made the right decision, but that doesn't help Alex with the fact that Kara is taking the loss of her aunt so hard.

Later, at Kara's apartment, she meets Winn, Alex and James. She tells them that the reason she imagined herself on Krypton isn't because she doesn't love them, but because the last few weeks she's been feeling lost, like when she first came to Earth, and that she chose to come back to Earth because she belongs here with her family.

Before they sit down to eat pot stickers and ice cream with James and Winn, Alex tells Kara that Henshaw tried to cover for her at work. When the conversation starts to descend into work stuff, James calls it off and says it's time for food and drink.